This invention can be used any time a user needs to “see” an otherwise invisible object placed within the setting in which it would normally appear, and in this case, onto a video stream. This form of image “augmentation” is known as augmented reality (AR). When a video camera, as opposed to a see-through setup (as might be done with partial mirrors) is used to capture the real scene, the result is considered video-based AR. A video-based AR setup has only a few basic components, including (1) a camera with a known field of view (FOV), (2) a method to determine the position and orientation of the camera, and (3) a computer that creates computer-generated virtual objects that correspond to what the camera is seeing by using the previous two components.
Typically, one of the physically largest components is the second one, wherein a tracking system is used to determine the position and orientation of the camera. A common method known in the art would use an external tracking system available from a company like InterSense (Burlington, Mass.), where the tracking system is made of two main parts. One part is a relatively substantial device that attaches to the camera, and the other part is a detection system that must be supported in place above the camera, usually by at least a few feet. While it has the advantage of being able to detect translational motion in addition to orientation, its size limits its utility.